A fully bio‐based benzoxazine, 3‐furfuryl‐8‐methoxy‐3,4‐dihydro‐2H‐1,3‐benzoxazine (Bzf), has been prepared using guaiacol, furfurylamine, and paraformaldehyde as raw materials. Its chemical structure has been characterized by 1H and 13C NMR, FTIR, and elemental analysis. The polymerization behavior of Bzf in the presence of methyl p‐toluenesulfonate (PTSM) has been studied by FTIR and DSC, and the thermal stability of the cured resin has been evaluated by thermogravimetric analysis. It was found that PTSM is a good promoter that serves to avoid thermal decomposition of the bio‐based monomer during the curing process at high temperature. In contrast to the situation with neat Bzf, the presence of PTSM (5 mol % for Bzf) significantly improves the polymerization behaviors, including a decrease in the polymerization temperature from 240 to 174 °C, a shortening of the time required to reach the gel point on heating at 200 °C from 47 to 20 min, and an increase in the char yield of the cured resin from 53 to 62%. Moreover, these observed experimental results on the promoting effect of PTSM are interpreted in terms of several possible mechanistic schemes, which involve a catalytic effect on the dissociation of CO bonds in both the coordination ring‐opening reaction and the rearrangement from a phenoxy structure to a phenolic structure. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

Polymer blends incorporating poly(ethylene terephthalate) (PET), polyamide-6 (PA-6), and a reactive compatibilizer (low molecular weight bisphenol-A epoxy resin-E-44) were prepared with the following E-44 weight percent concentrations: 0, 0.3, 0.6, 1, 3, 5, and 10. The samples was studied by a scanning electron microscope (SEM), a polarizing microscope (PLM), dynamic mechanical thermal analysis (DMTA), wide-angle X-ray diffraction (WAXD), a differential scanning calorimeter (DSC), infrared spectroscopy (IR), and mechanical testing. SEM and PLM showed noticeable changes in both the amorphous region and the crystalline region of the blends. The changes indicated better compatibility between the dispersed phase (PA-6) and the matrix (PET), which was further confirmed by the DMTA test. The WAXD showed that PET and PA-6 crystallized separately and no cocrystallite was found. The melting and crystallization data, obtained by DSC, suggested that the crystallization of the blend was blocked, although the hindered mechanism for the effect of E-44 on PET was different from that on PA-6. The notched impact strength and flexural strength of the PET/PA-6 blends were significantly improved when the content of E-44 was 5 wt % (improved about 500 and 400%, respectively). IR was used to study the reaction among E-44, PET, and PA-6. The result indicated that the grafting reaction and the crosslinking reaction occurred during melt blending. The obvious increase of mechanical properties and the reinforcing and toughening effect were attributed to the formation of the crosslinking net in the blend.

A novel Ca(2+) ion responsive particulate emulsifier, which is based on copolymer nanoaggregates, is reported in this work. Results from dynamic light scattering (DLS) and cryo-transmission electron microscopy (cryo-TEM) indicate that the formation of poly (4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSMA) nanoaggregates is strongly dependent on Ca(2+) concentration. The PSSMA copolymer only aggregates above a critical Ca(2+) concentration (0.2 M) with an average diameter of 10-40 nm. After dilution with water, PSSMA nanoaggregates are rapidly redissolved again. On the basis of the properties of PSSMA nanoaggregates, Ca(2+) ion responsive Pickering emulsions were successfully prepared. At high Ca(2+) concentrations, the emulsions with high stability against coalescence can be prepared with the size in the submicrometer range as determined by DLS. Cryo-TEM and dynamic interfacial tension results confirm the adsorption of PSSMA nanoaggregates at the interface, which is the key to the stability of the emulsions. More importantly, rapid demulsification can be achieved by dilution with water on demand. It is because, upon dilution with water, PSSMA nanoaggregates undergo a transition from stable nanoaggregates to individual polymer chains, which leads to interfacial desorption of nanoaggregates and rapid demulsification of emulsions. Thus, this finding presents a new manipulation on emulsion stability and is expected to provide a useful guidance in the fields of oil recovery, food science, environment protection, and so on.

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A series of blocked and branched waterborne polyurethanes (BBPUs) have been successfully synthesized and applied in pigment printing of cellulosic substrate. The branched structure was based on an "A 2 1 CB 2 " approach with diisocyanate prepolymer and diethanol amine. The terminal isocyanate groups were blocked by sodium bisulfite to lower curing temperature and improve the color fastness. The prepolymerization and chain extending could be considered as the end at 708C after 90 min and at 808C after another 90 min, respectively. It was suitable for sodium bisulfite to block isocyanate groups at 08C-58C for 40 min. The microphase separation of BBPU based on the longest polyethylene glycol (PEG) soft segment appeared. Both curing rate and pencil hardness of BBPU films distinctly reduced as the molecular mass of PEG soft segment ascended. The moisture rate increased from 18.1% to 49.2% with increasing the molecular weight of PEG, indicating that water resistance of the film became poor. Excellent acid and alkali resistances of the BBPU films were obtained. Color fastness to washing, rubbing, and light of the printed cotton fabrics was remarkably enhanced as the BBPU amount ascended to 10% which were cured at 858C for 6 min.